Mid-North Atlantic hydrothermal vent
In that very long period during which some 99.97% of Earth's history occurred prior to when creationists believe the Universe, Earth and life on it was created, the supercontinent, Pangea, split apart, then about 55 million years ago, North America and Eurasia drifted apart as did South America and Africa, opening up a rift which flooded to become the North and South Atlantic Oceans.
This coincided with an event called the Paleocene-Eocene Thermal Maximum (PETM) during which Earth's temperature rose by about 5-8 oC. causing a mass extinction. The exact cause of the PETM has been something of a puzzle for palaeontologists and geologists, until now.
When and what was The Paleocene–Eocene Thermal Maximum? The Paleocene-Eocene Thermal Maximum (PETM) was a short-lived period of rapid global warming that occurred approximately 56 million years ago. It is one of the most significant and well-documented hyperthermals in Earth's history. During the PETM, there was a dramatic increase in global temperatures and a perturbation of the carbon cycle.That mystery has now been solved by a large international team of geophysicists under the leadership of Professor Christian Berndt, Professor of Marine Geophysics at GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany, and Sverre Planke, Professor of Marine Geophysics at the University of Oslo, Norway, who have discovered that, the geothermal vents that opened up in the Mid-Atlantic ridge, actually formed in much shallower seas than was previously thought, and their venting of methane and other greenhouse gasses.
Key features of the PETM include:
- Timing: The PETM occurred at the boundary between the Paleocene and Eocene epochs, roughly 56 million years ago. It is typically dated to around 55.5 to 56.3 million years ago.
- Warming Event: Global temperatures rose significantly during the PETM, with estimates suggesting an increase of 5 to 8 degrees Celsius (9 to 14 degrees Fahrenheit) over a relatively short period, possibly as short as several thousand years.
- Carbon Isotope Excursion: One of the most distinctive features of the PETM is a significant negative carbon isotope excursion, which is indicative of a massive input of carbon into the Earth's carbon cycle. This suggests that a substantial amount of carbon was released into the atmosphere, potentially from the release of methane hydrates or volcanic activity.
- Ocean Acidification: The rapid release of carbon into the atmosphere led to the acidification of the oceans, which had significant ecological consequences, especially for marine life with calcium carbonate shells.
- Biological Effects: The PETM had profound effects on ecosystems. Many species went extinct, while others adapted or migrated to different regions to cope with the changing conditions. Mammals, in particular, saw significant diversification during this period.
- Duration: The PETM was relatively short in geological terms, with most estimates suggesting it lasted between 100,000 and 200,000 years.
The exact cause of the PETM is still a subject of research and debate among scientists, but it is believed to be related to the release of greenhouse gases, possibly from the decomposition of organic material, methane hydrates, or volcanic activity.
The PETM is of great interest to scientists studying climate change and the potential impacts of rapid global warming, as it provides a natural analog for understanding how ecosystems and the Earth's climate system respond to such events. It also serves as a cautionary example of the potential consequences of rapid carbon release into the atmosphere.
They arrived at this conclusion by examining core samples drilled from the ocean floor from the large igneous intrusions or large igneous provinces (LIPs).
From the GEOMAR Helmholtz Centre for Ocean Research news release:
About 55 million years ago, the Atlantic Ocean was born. Until then, Europe and America were connected. As the continents began to move apart, the Earth’s crust between them ruptured, releasing large volumes of magma. This rift volcanism has led to the formation of large igneous provinces (LIPs) in several places around the world. One such LIP was formed between Greenland and Europe and now lies several kilometres below the ocean surface. An international drilling campaign led by Christian Berndt, Professor of Marine Geophysics at GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, and Sverre Planke, Professor of Marine Geophysics at the University of Oslo, Norway, has collected extensive sample material from the LIP, which has now been evaluated.
In their study, published today in the journal Nature Geoscience, the researchers can show that hydrothermal vents were active at very shallow depths or even above sea level, which would have allowed much larger quantities of greenhouse gases to enter the atmosphere than previously thought.
"At the Paleocene-Eocene boundary, some of the most powerful volcanic eruptions in Earth’s history took place over a period of more than a million years," says Christian Berndt. According to current knowledge, this volcanism warmed the world's climate by at least five degrees Celsius and caused a mass extinction - the last dramatic global warming before our time, known as the Paleocene-Eocene Thermal Maximum (PETM). Geologists have not yet been able to explain why, as most modern volcanic eruptions cause cooling by releasing aerosols into the stratosphere.
Further studies of the Karoo large igneous province in South Africa revealed an abundance of hydrothermal vents associated with magmatic intrusions into the sedimentary basin. This observation among others led to the hypothesis that large amounts of the greenhouse gases carbon dioxide and methane could have entered the atmosphere through hydrothermal venting. "When our Norwegian colleagues Henrik Svensen and Sverre Planke published their results in 2004, we would have loved to set off immediately to test the hypothesis by drilling the ancient vent systems around the North Atlantic," says Christian Berndt. But it wasn't that easy: "Our proposal was well received by the Integrated Ocean Drilling Program (IODP), but it was never scheduled because it required riser drilling, a technology that was not available to us at the time."
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The authors show that the vent was active just before the Paleocene Eocene Thermal Maximum and that the resulting crater was filled in a very short time, just as the global warming began. Quite unexpectedly, their data also show that the vent was active in a very shallow water depth of probably less than 100 metres. This has far-reaching consequences for the potential impact on the climate. Christian Berndt: "Most of the methane that enters the water column from active deep-sea hydrothermal vents today is quickly converted into carbon dioxide, a much less potent greenhouse gas. Since the vent we studied is located in the middle of the rift valley, where the water depth should be greatest, we assume that other vents were also in shallow water or even above sea level, which would have allowed much larger amounts of greenhouse gases to enter the atmosphere".
As far as today's climate warming is concerned, there are some interesting conclusions to be drawn from the cores. On the one hand, they do not confirm that the global warming at that time was caused by the dissolution og[sic] gas hyrates – a danger that has been much discussed in recent years. On the other hand, they show that it took many millennia for the climate to cool down again. So the Earth system was thus able to regulate itself, but not on time scales relevant to today's climate crisis.
AbstractOf course, the primitive authors of the Bible whose scientific knowledge was so limited they thought Earth was a small, flat object with a dome over it that was in the center of the Universe, and ran on magic and had invisible sprits controlling things, could have had not the slightest idea of the real history of the planet; of plate tectonics and mass extinctions or the immense passage of time that had passed, because they lacked the science and technology to find out.
The Palaeocene–Eocene Thermal Maximum (PETM) was a global warming event of 5–6 °C around 56 million years ago caused by input of carbon into the ocean and atmosphere. Hydrothermal venting of greenhouse gases produced in contact aureoles surrounding magmatic intrusions in the North Atlantic Igneous Province have been proposed to play a key role in the PETM carbon-cycle perturbation, but the precise timing, magnitude and climatic impact of such venting remains uncertain. Here we present seismic data and the results of a five-borehole transect sampling the crater of a hydrothermal vent complex in the Northeast Atlantic. Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of the index taxon Apectodinium augustum in the vent crater, firmly tying the infill to the PETM. The shape of the crater and stratified sediments suggests large-scale explosive gas release during the initial phase of vent formation followed by rapid, but largely undisturbed, diatomite-rich infill. Moreover, we show that these vents erupted in very shallow water across the North Atlantic Igneous Province, such that volatile emissions would have entered the atmosphere almost directly without oxidation to CO2 and at the onset of the PETM.
But now we have found out and science is daily revealing information that utterly refutes the notion that those ancient, superstition scribes from the fearful infancy of our species wrote actual science and history, it is almost unbelievable that there are grown adults who have managed to remain so profoundly ignorant, in the Information Age, that they think those scribes wrote a much more accurate description of reality than anything science is revealing.
And for creationists there is again the little problems of all this happening millions of years before they think the Universe existed, and the fact that science is showing Earth to be so unstable geologically, that there are these regular natural disasters, sometimes local and sometime global to the extent that they cause a mass extinction of the life forms creationists think were created on a planet that was intelligently designed by perfect designer and fine-tuned for life.
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